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#1198586 - 12/06/2013 11:46 Re: Earthquakes [Re: cyclone sally]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
Hi cyclone sally,
That must have been very unnerving for you!

The general differences with earth tremors/quakes can involve the depth, composition of the structure (earth, rock etc.) of the epicenter of the quake and the surrounding land and/or sea floor; size of the 'shift'; reason for the movement; slow, gradual or sudden release of the energy (behaviour of the movement); what is powering the movement (e.g. plate shift, slip, grind, compression, spreading, ground or plate lift etc.); volcanic activity; impact (from above or otherwise) and so on.

The movement, whether it be vertical and/or horizontal can impact the nature of the resulting impact - rolling, shaking, dropping, rising, structure damage, pool water agitation, swaying, including liquefaction and so on.

The sound can come from the energy release and movements in the action of the plate, fault etc., reacting to stressors and faltering/moving. Sound is also emitted from cracks, grinds, breaks etc..
The prior noise can be sound waves proceeding, during and/or preceding feeling the subsequent movements.
Many people, including myself, have heard an EQ 'coming', as you describe like a jet approaching, taking off; a truck rumbling closer down a road or even a sudden explosion like a sonic boom.

There are what are called "P" (primary) waves and "S" (secondary) waves associated with quakes. description here Generally during the "P" wave phase (if I am correct here) one can feel a kind of dizziness or feel slightly off balance. After the "P" and "S" waves have been and gone, one can feel nauseated by degrees (some do and some don't). It can occasionally be like the effect of the 'shock' waves of a bomb/explosion going off.
This same exertion of energy leaves, for example, the water in the pool sloshing around for a while, during and after the tremor, as it has been physically moved and before it stabilizes again, the energy in the water is transferred back and forth, with the walls of the pool counteracting each bout of the side to side energy still pent up until all this energy is gradually dissipated/dispersed.

Recently, Hawaii experienced a moderated (M3++) tremor, which at first appeared not to disturb the water too much, But in the hours afterwards, I noticed sea level and current disturbances, sweeping around some parts. So after a quake has occurred, water can display various degrees of agitation, even what appears to be a 'delayed response'.

I think the loudest noises come from movements which are substantial and/or sudden in momentary release/slip/grind/break/compression (etc.).

Other 'noises' can come from magma and gaseous happenings occurring 'below', amongst other things.

Some earth movements/tremors/quakes can be 'quiet' as the movements/actions associated with them may be more 'fluid' (smoother), more 'slidy', less sudden or very deep in nature. But I don't feel I have explained this very well. I'll see if I can find out some more info...

I have jotted this rather quickly, so I may have missed some bits and I maybe wrong with my observations here and there. I may re-read this later and correct myself. wink

Cheers, Duck.

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#1198597 - 12/06/2013 12:44 Re: Earthquakes [Re: duckweather]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
Just to add to above post...there are some movements (albeit subtle) running through Vic atm. Where I am sitting, I can hear and feel it slightly... Leon Mow seismo

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#1198608 - 12/06/2013 13:40 Re: Earthquakes [Re: Lindsay Knowles]
cyclone sally Offline
Weather Freak

Registered: 26/01/2011
Posts: 83
Loc: 40km south of Gladstone
Duckweather...what an excellent explanation of why each earthquake can feel so different. Thank you for your time and trouble explaining it to me (and others.)We often chat about earthquakes over here and I now feel I can add some knowledge to the conversation!

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#1198615 - 12/06/2013 14:01 Re: Earthquakes [Re: cyclone sally]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
Cheers cyclone sally.
As I always say here and on my blog - I am an amateur regarding this science. So my comments are from personal observation, gut feelings and some knowledge.
Vanuatu is a lovely place (you lucky thing). We have various friends (and some of their families) in Vanuatu, Fiji, Solomons and some other islands.
Best wishes to you
Duck. wink

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#1198798 - 13/06/2013 12:03 Re: Earthquakes [Re: duckweather]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
Just spent some brief lazy time looking up some studies/articles on the regions where the tremors/EQ's have been occurring in the NT/WA and NT/SA border regions.
One I found interesting reading and has a map of some fault lines in the NT is called "Deep Seismic Reflection Profiling In The Northern Territory: Past Work And Future Directions" - here - by R. Korsch, B. Goleby and E. Chudyk

The landscapes of these regions is very interesting. Visually, you can see a distinct east - west structuring (ridges) of the land form/escarpments.

"The Origins Of The Intraplate Stress Field In Continental Australia" [Earth and Planetary Science Letters 133 (1995) 299-309] is fascinating reading. I am going to re-read this article again to get the full gist of it.

If you like maps, like I do, here's a site with multiple maps of Oz, including a map on the Cratons of Australia - Global Security (dot) org - Australian Maps

The tremor/activity in Oz seems to have been on the increase lately......

I hope you find this post interesting smile

Cheers, Duck.

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#1199007 - 14/06/2013 11:48 Re: Earthquakes [Re: duckweather]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
The M6.7, near Christmas Island and south of Java, "...is a shallow outer rise tensional event due to plate bending into subduction zone. This Oceanic plate is bending and the stresses in this plate have triggered the earthquake." source - The Watchers

If you have a look at the buoy in event mode on National Data Buoy Centre's website, click on the 'flashing' diamond below Indonesia and you will see that before the quake the readings were very jittery. I was watching this and felt that it was a prelude to a considerable EQ.

Another buoy in event mode is east of New Jersey, USA east coast. This weather system may have something to do with this buoy response - Severe weather US east and Atlantic

Cheers, Duck.



Edited by duckweather (14/06/2013 11:54)
Edit Reason: extra

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#1199078 - 14/06/2013 19:47 Re: Earthquakes [Re: duckweather]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
This is not an actual EQ, but it shook the ground in the surrounding area and more importantly, it took the life of one person and injured 77 others - yet another chemical plant explosion in the US -
Geismar chemical plant explosion

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#1199104 - 14/06/2013 22:00 Re: Earthquakes [Re: duckweather]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
Hawker in South Oz has just had an M3. I was watching Hawker's seismo when it occurred and there seemed to be no prior movement to signal a possible tremor...so this must have been a bit of a sudden jolt. Anyone in SA feel it? According to Geoscience it was about 0kms deep.

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#1199118 - 14/06/2013 22:59 Re: Earthquakes [Re: Lindsay Knowles]
Fyne Offline
Weather Freak

Registered: 16/02/2010
Posts: 123
Loc: NW Brisbane
Please keep it coming Duck, it's fascinating trying to connect the seismic dots and to make sense of elemental forces more enormous than anything we can alter, yet.

I take a keen interest in this, just don't necessarily have the time with work, family etc to interpret it.

So thanks for the posts smile
_________________________
Sunshine is delicious, rain is refreshing, wind braces us up, snow is exhilarating; there is really no such thing as bad weather only different kinds of good weather.

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#1199125 - 15/06/2013 00:21 Re: Earthquakes [Re: Fyne]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
Gee..thanks for your lovely words Fyweather wink
I try, when I get time to post info, links and my own feelings (pre and post events) about EQ's and related stuff, which I hope others may find interesting and informative.
There is also alot of info I don't get to post here and on my blog, due to lack of time.
Nature/Earth never ceases to fascinate me.

I feel there are 'things' going on in the geological world (EQ's, etc.) which are 'unknowns' currently, and as you say - joining the dots, perceiving what the unknown is/maybe and marrying this with the 'known' is the challenge sometimes for scientists and amateurs (like this daffy Duck). Much of my thoughts run on intuition, rather than in depth knowledge - sometimes I can be wrong.

I feel that there will be recognition of some newer fault lines in Oz, or this could be old ones being discovered. I also get a gut feeling that what is/maybe happening 'below' with some of Oz's tremors, may begin to show surface/land signs here and there (meaning maybe observable minor ground lift or drop; fissures (cracks) and maybe inland water table/salinity issues). Now....these are feelings only, not predictions of actual events.

Cheers, Duck.

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#1199233 - 16/06/2013 08:57 Re: Earthquakes [Re: duckweather]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
Good morning folks.
Overnight (our time) Crete and Nicaragua have experienced substantial quakes (M6's [+]).
The Nicaraguan quake, off shore, generated the need for a tsunami warning (potential watch only), as it was deemed that this quake may have the potential to spawn a small tsunami. I am quite sure there would have been some water level/behaviour disturbances of a minor nature.
Crete has been experiencing multiple aftershocks since their M6.2.
More news on these quakes will eventuate during today.

I get a feeling that Hawker in South Australia has just had an M3? about an hour ago. The seismo's in SA have registered what appears to be a 'local' movement, which I am guessing the culprit may be in the region of Hawker.

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#1199370 - 16/06/2013 23:25 Re: Earthquakes [Re: duckweather]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
Hi folks. I've been busy today and am now catching up on what's been going on on the EQ front...

So for the moment, I'll jot a link to an article, titled " High-Speed Geology: Violent Seismic Activity Tearing Africa in Two" By Axel Bojanowski , which is very interesting reading and quite curiously 'answers' or confirms some of my feelings (and silent questions) I have had regarding this region.
This article is dated January 20, 2011. Though it is a couple of years old, I will see if I can find some more up-to-date info or an update on this report.

For now, Duck.

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#1199457 - 17/06/2013 16:45 Re: Earthquakes [Re: duckweather]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
Geoscience has just put up on their site that EQ/tremor I mentioned in Hawker, South Australia (in a previous post) that I suspected had occurred.

Crete is still experiencing subtle then substantial EQ'/tremors. It might take some time for this region to stabilize.

Kamchatka and Japan may come up with some movements very soon.

Bit more later.....


Edited by duckweather (17/06/2013 16:46)
Edit Reason: spelling again

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#1199469 - 17/06/2013 17:36 Re: Earthquakes [Re: duckweather]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
Just adding some of those articles/info that I like to offer up to all you folks occasionally, as I find them... smile

"Earthquakes Turn Water Into Gold" - news.discovery.com

Also from discovery.com "Boom! Super Seismo-Sonic Earthquakes Are Real"

Also adding some other interesting articles on the tsunami thread...

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#1199499 - 17/06/2013 19:33 Re: Earthquakes [Re: Lindsay Knowles]
Petar @ Sdny Offline
Weather Freak

Registered: 09/03/2007
Posts: 597
Loc: South West Sydney
I don't know how much you know about this website: http://solarwatcher.net/

But I find it a great insight. Further uptick to a major quake watch is happening at the moment. We are in for a busy period.
_________________________
Latest Earthquake data contributions - Updated as they come in: http://www.emsc-csem.org/Earthquake/seismologist.php

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#1199508 - 17/06/2013 20:38 Re: Earthquakes [Re: Petar @ Sdny]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
Hi T.C. T/P

That is an interesting site - as it goes further than I do (a different approach) to tie in solar happenings with potential influence on EQ's. There is alot of merit and practical application in this perspective.

I am always interested in these kind of correlations and admire the work these people/bloggers put in and their focus (and the results on many occasions).

Call me an old flower-child, and some might grin , I try and stay true to my intuitive perspective regarding EQ's etc.. with a definite interest in the science perspective and the perspective of those who 'think-outside-the-square' - trying to piece the signs/signals and observable 'behaviours' of our beautiful planet (and solar) together.
I wish I had more time to be more thorough and focused on my EQ interests.

I too believe (my good old feelings/intuition) that we may be in a 'beginning' and/or continuing period (length of time??? - maybe over the rest of 2013) of some substantial and maybe impactful earthly activity. As I have mentioned in my blog, I feel that maybe water issues, meteorites, emissions from volcanoes and some powerful EQ's may be on the rise and/or intermittent features for May/June (and spaced over 2013).
There may be lulls in 'activity' which may leave many to become 'complacent' by degrees about further potential happenings. Then an event may occur to stun many or raise intense interest. (I am being deliberately rather vague here, and I don't like being a dramatist..)
The earth (and other reaches) have always done their own thing, of which we are at their mercy mostly. So what I mention is probably fairly predictable in the scheme of things anyway....sometimes I am accurate (if I may say so myself...)

Cheers, Duck. wink

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#1199605 - 18/06/2013 12:34 Re: Earthquakes [Re: duckweather]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
Inland on the Californian coast, Mammoth Lakes (Long Valley area) in the mountain ranges, is experiencing a cluster of tremors between M1 and M3 atm.
Nearby is the Yosemite National Park and the tremors are quite shallow and not occurring near the major plates in the region.
Global Incident map - Earthquakes

This activity, which has been going consistently for the last 2 hours or so, could be a prelude to a moderate EQ/tremor or a situation similar to a recent cluster in another part of California where the behaviour settled after a day or so.

There are also the occasional small tremors happening over the border into Nevada to the east.



Edited by duckweather (18/06/2013 12:35)
Edit Reason: extra

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#1199610 - 18/06/2013 13:05 Re: Earthquakes [Re: duckweather]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
Not sure how old this article is but I'll jot the link to it anyway -
"GEOLOGIC HAZARDS AT LONG VALLEY CALDERA"

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#1199631 - 18/06/2013 16:47 Re: Earthquakes [Re: Lindsay Knowles]
GDL Offline
Weather Freak

Registered: 17/02/2008
Posts: 630
Loc: Bowen Mountain NSW
Not a good place to invest in real estate me thinks. ........GDL

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#1199646 - 18/06/2013 17:42 Re: Earthquakes [Re: GDL]
duckweather Offline
Weatherzone Addict

Registered: 20/12/2010
Posts: 2769
Loc: Wantirna, Vic
Hi GDL...there seems to be a few places in the US which are proving to be a bit troublesome. Some regions along the west coast, including some near shore islands; some points along the Mississippi, central south-east US and so on, are continuing to experience happenings such as sinkholes, landslides, water issues for example.
Though, there are also many other regions around the world which are experiencing interesting, horrible and some unnerving, issues too.
It all makes me feel pleased to be on what I think is fairly firm ground, even if it seems a fault line in Vic points in my general direction eek
I feel for all those folks around the world who are losing their homes (and some lives) to the issues mentioned above.

Cheers Duck.

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